Hewlett-Packard thinks it can build data centers faster and more cheaply by using standard, pre-built components that are assembled on site in a "Lego-like" fashion.

Its Flexible Data Center, announced Tuesday, consists of four large data center halls, or quadrants, that are built around an operations building in the center. It's constructed from prefabricated sheet metal parts, and the quadrants, each about 6,000 square feet, can be added one at a time as a company's capacity needs increase.

It's a big departure from traditional brick and mortar data centers, which are usually designed on a custom basis and take more than a year to build. Using standard designs and factory-built components, HP says it can reduce construction costs by a half and get a new data center up and running in four to six months.

"We came up with a Lego-like concept, an industrialized approach to data center design," said Kfir Godrich, a CTO in HP's Technology Service group. The data centers are also highly energy efficient, he said.

HP came up with the idea after talking with some of its large customers. Many of them have data centers that are low on capacity, but they but are unwilling -- or unable -- to foot the bill for a new facility, especially when that involves having to forecast what their capacity needs will be a decade or more into the future.

A prefab structure can help solve that problem, allowing companies to start small and add new modules as their demand for compute power increases, said Michael Qualley, a senior vice president with IT consulting company Forsythe Solutions Group.

They won't be suitable for all types of applications, he said, but are a good fit for companies building highly virtualized environments -- big farms of x86 servers like those used by cloud service providers such as Amazon Web Services, or by corporations building private clouds to deliver services like virtual desktops.

HP isn't adhering to the Uptime Institute's tiering system, Godrich said, which companies use to figure out if design has sufficient redundancy and reliability to meet their applications' needs. "With the enterprise cloud, we don't think most applications are going to be high-availability, critical applications," he said.

HP isn't the first to offer such a product. Colt, a U.K. telecommunications company, announced earlier this month that it is also selling factory-built data centers that are assembled on site and can be expanded as demand dictates.

They are an alternative to containerized data centers, which cram IT equipment into a shipping container and are another option for expanding data center capacity quickly.

Godrich said the Flexible Data Center has a PUE (power usage effectiveness) rating of 1.2. It's a measure of how much power supplied to a data center actually reaches the IT equipment, and any rating lower than about 1.5 is considered highly efficient. Most existing data centers have an average PUE of about 2.0.

HP achieves the low PUE with some novel options for power and cooling. Unlike traditional data centers there's no raised concrete floor to circulate cold air, which adds to construction costs, and there is no chiller, normally a big part of the mechanical cooling infrastructure.

Instead, HP offers several container-based options for power and cooling that attach to the outside of each data center hall. They include evaporative cooling systems, and an air handler from vendor KyotoCooling. It says it will work with customers to figure out the best option for their local environment.

"The power and cooling modules connect directly to the data center quadrant so there is no piping or heavy installation work; we're trying with all of this to minimize labor costs at the site," Godrich said.

"There's no raised floor, we just push air into the volume of the quadrant, using a hot-aisle configuration, and take it back out through the ceiling and back to the cooling unit."

Each quadrant can support 800 kilowatts of server equipment, and the structures are intended to last for 15 years, much like a traditional data center. 'These are not temporary," Goodrich said.

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